Brake system for automotive vehicles



May 9, 1933. c. sA BRAGG ET AL 1,908,400

BRAKE SYSTEM FOR AUTOMOTIVE VEHICLES Original Filed March 28, 1928 ATTO R N EY Patented May 9, 1933 j UNITED" STATES PATENT; OFFICE CALEIB S. IBRAGG, OIE PALM BEACH.,` FLORIDA, AND VICTOR W. KLIES-B/ATH, OF PORT WASHINGTON, NEW YORK, ASSIGNORS TO BBAGG-KLIESRATH CORPORATION, OF LONG ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK BRAKE SYSTEM FOR AUTOMOTIVE VEHICLES Original application led Hatch 28, 1928, Serial No. 265,255. Divided and this application iiled April 16,

1929. Serial No. 355,619.

Our invention consists in the novel features hereinafter described, reference being had.to the accompanying which shows an embodiment of the invention selected by us for purposes of illustration, and the said invention is fully disclosed in the following description and claims.

Our present invention relates to vacuum or suction actuated brake systems for automotive vehicles, in which the suction or rariication is conveniently obtained by a connection to the throttle controlled portion of the suction passage of an internal combustion engine which drives the vehicle, and in which the higher pressure fluid, usually atmospheric air, is at a substantially constant pressure, and it consists in the provision of the herein described pressure regulating check valve interposed between the'said portion of the 'suction passage of the engine and the controlling valve mechanism for the suction actuated device for automatically maintaining a constant and predetermined degree of rarication available for the operation of the suction actuated device, and providing means under the control of the operator for varying said constant degree of rariiication from time to time to meet changes in the coeiiicient of friction between the Wheel tires and the roadjsurface, due to variations in road conditions and also to variations in the load ofthe vehicle, so that the operator may be enabled to apply the brake mechanisms with the maximum force of the Iactuator without locking the wheels. The pres-` sure regulating valve also functions as a check `valve to prevent variations in the de. gree of rarication which occur in the in- 1 take manifold from being transmitted through the controlling valve mechanism to the power actuator when the latter is connected with the suction passage to apply the brakes by power, where the piston 'of the actuator is normally submerged'in atmosf phere in the released position and the actuator is not provided witha. vacuum storage reservoir. The apparatus further serves as a check valve if a ivacuum storage tank is used, with the' type of actuator referred to,

to maintain a vacuum storage in the tank sufHcient to insure an emergency application of the brakes should the motor stall. Also where the actuator piston is submerged in vacuum l,in the released position, as shown for example in our former Letters Patent of the United States No. 1,583,117 dated May 4, 1926, in which case the portion of the actuator cylinder forward of the piston serves as a vacuum storage space, the apparatus performs 'a like function. The apparatus also serves as a-check valve to prevent gaseous mixture from the suction passage which might otherwise be drawn intothe suction pipe by reason of the fluctuations in the defeatures of construction and combination of parts hereinafter fully described and particularly pointed out in the claims.

This application is a division of our former application for Letters Patent of the United States filed March 28, 1928 and given Serial No. 265,255.

In the accompanying drawing,

Fig. 1' is a diagrammatic view of an installation of brake mechanism in an automotive vehicle showing our invention embodied therein, in connection with an actuator, the piston of which is submerged in atmosphere when in the released position.

Fig. 2 is` an enlarged sectional `view of the pressurefregulating check valve shown in- Fig. 1. 1 v

Fig. 3 is a sectional view of the controlling valve mechanism for the actuator, illustrated in Fig. 1.

In the drawing we have shown our invention -appliedo a brake system for an autol motive vehicle in connection with a power actuator of the type in which the piston is -normally maintained submerged in atmosphere, (or in other words the higher fluid pressure) when in the released or oif position. The power actuator consists in "this instance of a cylinder, l, open to the atmosphere at one end and closed at the other end, and h-aving a piston, 3, in the cylinder` operatively connected with brake mechanisms of the vehicle, indicated as a whole at B, which may be of any desired type, but which are shown, for example, as comprising each a brake drum, 70, brake ban-d, 71, brake applying lever, 72, having a retracting spring, 73, said brake lever being connected by a link rod, 74, with arms, 75, on a rock shaft, 76, having an arm, 75a, connected with a piston rod, 5, of the piston, 3.

The actu-ator is provided with means for connecting the cylinder between the piston and the closed end of the cylinder with a source of suction and with a source of hlghp er iuid pressure under the control of suitable controlling valve mechanism, which may be of any desired type. In this instance we have shown the controlling valve mechanism located exterior to the actuator, in linkage between`the operator operated part and the brake mechanisms, and comprising a valve casing, 10, connected by a link rod, 78, with `a foot lever, 80, having the usual retracting spring, 81, the valve casing being provided with oppositely disposed valves indicated at 42, 43, operatively connected with a hollow valve actuating part, 20, which is connected4 by a link, 77, with an arm, on the rock shaft, 76, thus connecting it with the piston, 3, and with the brake mechanisms. The particular construction of the valve mechanism herein shown is covered by our Letters Pat.- ent of the United States, No. 1,731,041, and forms no part of our present invention, and will not befurther described in detail except to say that the relative movement of the valves with lrespect to the casing controls the actuator, and that the amount of lost motion between the valve actuating part and the valve casing is limited by 'suitablemeans, as collar, 28, on the part, 20, and an adjustable sleeve, 22, secured to the casing, to enable the operatorto apply his physical force to the brake mechanisms in addition to that of the actuator, orto apply the brake mechanismsdirectly by physical force in case of failure of power. It will also be understoodthat the valves engage the valve actuating' part. 20, with a sealing fit, and are normally pressed toward their seats by yielding means, as a` a flexible pipe, 15.- The valve casing is pro-A vided withan inlet, 16, on one side of the valves for the' higherpressreiiuid, which in this instance communicates with the at.

mosphere, an-d said casing has an outlet aperture, 17, on the other `side of the valves, communicating by suction pipe, 426, 426, with the throttle controlled portion of the suction passage, 61, (as the intake manifold, 62) of an internal combustion engine, 60, forpropellingthe vehicle, being connected to the suction passage between the throttle valve,

indicated at 63, and the engine cylinders, the

`nism for the actuator and the throttle conone, end and provided at the other end with a cap or cover, 431, screwed or otherwise secured thereto and having an air inlet aperture, 432, communicating. with the atmosphere and a centrally located guiding sleeve,

433. AThe valve caslng' is provided with an,l outlet passage having a tubular portion or standpipe, 434, extending into the interior of the casing and forming what we term a partition member, which divides the interior of the valve casing into a chamber, 434, within the tubular member or standpipe, and the chamber, 435, within the casing surrounding the standpipe. In this instance the standpipe is provided with a seat, 434", at its inner extremity to be sealingly engaged by a seat portion, 437, secured to a flexible diaphragm, 436, or pressure operated member,

which has its outer edges in sealing engagement with the valve casing and preferably clamped' as shown by the cover, 431. The standpipe is also provided with an annular shoulder, indicated at 434, which forms a second annular seat surrounding the seat, 434", and adapted to be engaged bythe inneredges of a "flexible ring orannular check valve, 436b, having its outer marginal portions in sealing engagement with the outer edges of the casing and preferably clamped in engagement therewith by the cover. 431, a spacing ring orwasher, 431, being inserted between the outer edges of the ring, 436", and the edges of the diaphragm, 436. The diaphragm, 436, is provided with a stem, 439, connected with-the diaphragm and the reinforcing portion thereof, (if that is used) by an air-tight connection, said stem exi ing device between the spring, 450, and the hand operated device, as the lever, 51, and

in this instance we have shown a threaded eye-bolt, 50h, provided with an adjusting nut, 50, for connecting the spring, 450, with the link, 50a. The stationary part, as the ratchet segment, 53, is conveniently provided with indications such as the words `Dry Slick lice Loaded Medium Light for example, or other suitable indications, to indicate variations in the coefficient of friction between the vehicle wheels and the roadway. These variations may be due either to the condition of the road or the load condition of the vehicle to which the adjusted positions of .the hand operated lever, 51, correspond and in which positions of the lever the tension of the spring will be such as to provide the desired maximum rarilication for operating the brake mechanisms by power to the -maximum extent of the actuator without locking the wheels to which the brakemechanisms are applied. The special adjusting means, 50h, 50, permit of Calibrating the spring to secure the desired tension thereof in the different positions of the hand regulating lever, 51. The hand regulating' device or lever, 51, is located within convenient lreach of the operator, for example on the dash or instrument board.

The chamber, 434, within the standpipe,

the throttle controlled portion of the suction passage of the engine, and the chamber, 435, Within the valve casing outside of the standpipe is connected by a pipe, 426, also forming with the pipe, 426, a part of the suction line,

actuator, in this instance through the vacuum storage tank, 26". The diaphragm, 436, when the engine is in operation, is exposed to a differential of luid pressures, to, wit, the differential between the atmospheric pressure on its outer face and the sub-atmospheric ypressure within the casing, 430, or within the standpipe, 434, or both. The tension ofthe spring, 450, tends to pull thevdiaphragm, 436. and its seat engaging portion, 43,7, in a direction away from the seat, 434", at the linner end of the standpipe in opposition to the `dierential of uid pressures acting onthe diaphragm. lf the hand'operated lever, 51, is in such position that the spring, 450, exerts 434, is connected by the suction pipe, 426, with with the controlling valve mechanism for the practically no tension on the diaphragm when the engine is running, and if the motor is then started and the throttle valve is closed, to produce rarification in the suction passage, 62, and the suction pipe, 426, and the chamber, 4341, Within the standpipe, 434. Air will also be exhausted from the surrounding chamber, 435, and the spaces connected therewith, through the pipe, 426, and in the vacuum storage tank, 26", (if the latter is used) and when a comparatively slight degree ofl rarication is created within the chambers, 434a and 435, the diaphragm, 436, will .be moved inwardly by the air pressure on its outer face into engagement with the seat, 4341, thus cutting oli the connection between the chamber, 435, and the suction passage of the engine, and a comparatively small degree of rariication will be maintained available for the operation of vthe actuator or actuators. As the tension of spring, 450, is increased by the adjustment of lever, 51, the diaphragm, ,436.Will be held unseatedv until the degree of rarification within the valve casin subjects the diaphragm to a differential o uid pressures suiicient to overcome the tension of the spring, 450, as adjusted, and thus provide a greater degree of rariication available for the operation of the actuator.

The operator may, therefore, by adjusting the hand operated lever, 51, regulate the degree of rarifcation available for operating the suction actuated power actuator,an`d the maximum available rarification will be provided when the tension -of the spring is substantially equal to the maximum differential of fluid pressures on the diaphragm, which amounts to approximately 10 pounds per square inch, that is to say, the difference between atmosphericpressure and the maxi` mum rarification obtained'in theintake manifold of the engine, which is represented approximately by 20 inches of mercury.

ln this construction it 'is immaterial Whether or not the relative cross-sectional areas of the chambers, 434a and 435, are such lthat the differential of fluid pressure on the diaphragm will hold the valve portion, 437, seated in case of a rise of pressure in the standpipe or chamber, 434B. Any rise of pressure within the standpipe abovev that in the chamber. 435, of the casing, if suicient to unseat the diaphragm, 436, would immediately increase the pressure on the outer face of the annular check valve, 436", and seat it upon its seat, 434C, so as to prevent any rise of pressure within the chamber, 435. Such a rise of pressure may occur, for example, when the throttle valve is more or less opened or should the engine stop. The apparatus, therefore, acts efficiently as a check valve and lwill maintain a suiicient degree of raricathe motor stall during or after an application of the brakes.

When a vacuum storage reservoir or tank is used'as shown in Fig. 1, or where the actuator cylinder is normally maintained submerged in vacuum as shown inour former Letters Patent hereinbefore referred to, the vacuum will be held for an emergency application of the brakes even if the engine should stall or be stopped. The device will also prevent the gaseous mixture from being carried into the .suction pipe, vacuum reservoir and connected spaces, by the liuctuations in the degree of rarification within the intake manifold, due to the o ening andfclosing of the throttle valve, as or example whenthe throttle valve is opened fully after it has been previously closed and the maximum degree of rariication has been produced in the reservoir and its connections, which gaseous mixture might find its way into the cylinder of the actuator. If the gaseous mixture was not `prevented from being drawn into the suction pipe, the accumulation of liquid fuel which would result might find its way into the suction actuated device and destroy the lubrication thereof and injure the valves and packings, and it might also cause an eXplosion in the pressure regulating check valve or in the suction actuated device should the motor backfire.

The pressure reguating check valve also prevents variations in the degree offrarification in the intake manifold from being transmitted through the controlling valve mechanismJ to the power actuator when the controlling valve mechanism is in a position to connect the power actuator with the suction passage, and the brakes are being applied by power of the actuator. v y

It will be understood that when Vit is desired to apply the brake mechanisms by power, assuming that the engine is running andthe throttle valve closed or partly closed, the operator will depress the foot pedal, 80,

i .and shift the valve casing and valves with respect to each other, so as to `connect the actuator cylinder, 1, forward of the piston with the suction pipe, 426a. Air will be withdrawn from the actuator cylinder, 1, into the chamber, 435, of the valve casing, 430,

thereby increasing the pressure on the inner face of the diaphragm, 436, and reducing the differential of fluid pressures, tending to "chamber increases to such a point that the differential offliud pressures on the" diaphragm overcomes the resistance ofthe spring as adjusted, whereupon the diaphragm will seat. The withdrawal of air from the actuator cylinder forward of the piston permits the pressure of the atmosphere on the rear face of the piston to move the piston forward and apply the brakes with a maximum force dependent upon the differential between the atmospheric pressure on the piston and the degree of rarification' available to the actuator under the control of the pressure regulating check valve. It is obvious therefore, that by adjusting the tension of spring, 450, the maximum capacity of the suction actuated device to apply the brake mechanisms may be varied under the(y corrtrol of the, operator independently of the does, result. O bviously a maximum braking power, which may be safely applied to the wheels of a loaded vehicle on a dry roadway, without danger of locking the wheels, will lock the wheels when the vehicle is lightly loaded, or is moving over wet or muddy, or snow or ice covered roads. It is desirable, therefore, that the operator be provided with just the amount of maximum available power the brakes require, without locking the wheels under these varyin conditions, independently of the controlling valve mechanism for applying the brakes. It has, furthermore, been found desirable, and has become general practice with vacuum brake systems, to force the operator to do a certain amount of physif cal work, either while applying the brakes by power, or to supplement the power applications of the`brakes with physical force for a full application of the brakes. In the latter case, the physical force exerted by the driver is directly applied to the brake mechanisms, in addition to the force being applied by the power cylinder connected therewith, with the result that on wet or icy streets, the operator will have very little feel of the amount of work being done by the brake cylinders, due to the fact that the chassis will be locked by power applications alone before any pressure has been built up on the pedal lever to reduce the-force o'f the power actuator to any,

desired extent, so\that he may haveafu'll and natural feeling of resistance on the foot pedal without locking the wheels by power applications of the brakes, regardless of road conditions or load conditions, and there is therefore less danger of applying the brakes unintentionally with so much power as to lock the wheels. This is readily accomplished according to our invention, by adjusting the tension of the spring, 450, by v means of the hand lever, LL51, and its locking means, as before described.

What we claim and desire to secure by Letters Patent is A l. In a brake system for automotive vehicles, a combined pressure regulating and check valve adapted to control differentials of fluid pressure, comprising a valve casing having a chamber provided with means for connecting it with controlling valve mechanism, means providing an outlet passage, said last mentioned means having a tubular portion extending into said chamber, and open thereto at its inner end, an impervious pressure operated part forming a wallv of said chamber, and provided with portions for closing said outlet passage to disconnect it from the said chamber, and having its outer Jface exposed at all times to the higher of differential fluid pressures, actuatin said first mentioned valve mechanism t ereby acting to move it toward its closed position, yielding means connected with said pressure operated part and tending to hold it in open position, the said tubular portion of said out# let means being provided with an annular seat at a distance from the portion engaged by the said pressure operated part, and a. flexible annular check valve member in said chamber having its exterior marginal poradapted to engage said first mentioned seat, yielding means connected with said pressure operated part acting thereon to hold it 1n unseated position, said pressure operated part having its outer face exposed at all times to the higher of dierential Huid pres- Vsures actuating said first mentioned valve mechanism, a flexible annular check valve member having exterior marginal portions in sealing engagement with the valve casing and interior marginal portions in position to engage said second mentioned seat, said pressure operated part being held seated whenever the differential of Huid pressures thereon is suiiicient to overcome said yielding means, whereby a substantially constant maximum differential of fluid pressures lis maintained by said valve mechanism.

In testimony whereof we aiiix our signatures.

CALEB S. BRAGG. VICTOR W. KLIESRATH.

tions in sealing engagement with the walls of said chamber, and inner marginal portions for engaging the said annular seat, to separate said outlet passage from the said chamber by a rise of pressure in said passage above that in said chamber, and handoperatedf.

means accessible to the operator while the vehicle is moving, for varying the tension of said yielding means.

2. In a brake system cles, 4a combined pressure regulating and check valve, comprising a valve casing closed at one end, fluid .transmitting connections extending from said casing, a tubular outlet member within said casing, open at its inner for automotive vehiend and provided with an annular valve seat l and a-second annular valve seat in a dierfk ent transverse plane from the rst mentioned! seat, said outlet member being connected with one of saidv Huid transmitting connections, means or connecting a portion of aY second valve casing surrounding said outlet member with another of said iuid transmittmg connectlons, a'pressure operated part having marginal portionsin sealing engagement with said casing, and central portions CERTIFICATE OF CORRECTION.

Potent No. 1,908,400. May 9., i933.

CALEB S. BRAGG, ET AL.

it ishereby ce1-titled that error appears in the printed specification of the abovenumbered patent requiring correction as, follows: l Page 1, line 3, .after "accompanying" insert the word drawing"; page' 5, lines 60 and 6l, claim 2,

' for' "a secontl" read "said"; and that the said Letters Patent shoultibe read with these corrections therein that the same may conform to the record o the case in the Patent Office.

Signed and sealed this 22nd day of August, A. D. 1933.

YM. J. Moore.

l(Seal) v Acting Commissioner of Patents. 

